The manoeuvres undertaken to take way off the vessel did not produce the expected results because the helm was turned hard-to-port while the vessel still had a fair amount of way on. As the propeller's pitch is to the right, it was normal to use the helm to counter the vessel's tendency to turn head to starboard when the engine was set to full astern. This tendency to turn to starboard is greatest when the vessel stops making headway through the water. When the helm was turned hard-to-port, the vessel began to turn immediately, and under the effect of the current, the turn was much sharper than expected. The shoal near the south shore downstream of the Saint-Louis Bridge is about 250 m from shore and 300 m upstream of the high-tension hydro towers, the approximate position of the GRANT CARRIER when she began manoeuvring to return to the channel. This shoal is covered with 4.26 m of water at chart datum, and the vessel's after draught was 7.98 m. At 0117, an electrician was dispatched to the Saint-Louis Bridge to determine the cause and attempt a repair of the malfunctioning green lights. The source of the malfunction was found to be switch No. 42D, as shown on one of the plans of the bridge. This switch performs two functions: it stops the bridge when the span has reached its raised position, and it activates the lights. There is a second switch (No. 42D1) that stops the bridge if switch No. 42D does not work properly. However, this second switch only stops the vertical motion of the bridge; the lights are not connected to it. Switch No. 42D was worn to the point where the light's electrical contact could not be made on the first and second tries. The contacts used to stop the span in the open position functioned properly, but the second function of simultaneously activating the lights with a different set of contacts did not work, and the bridge operator was unable to do this manually. Once the bridge operator activates the bridge opening/closing control, the bridge rises or descends to a predetermined point just before the operation is completed, whereupon it slows down to reach its final position, and stops automatically. The operation can also be performed manually. As the bridge's green lights did not come on when the span reached the open position, the bridge operator could not authorize the vessel to pass. The lights serve only to control traffic and/or give authorization to proceed. Even though the green lights did not come on, the vessel could have passed under the bridge safely. However, authority to allow vessels to proceed in such circumstances rests with the Saint-Lambert Traffic Control Centre (Seaway Beauharnois), which has jurisdiction in this area. The weight of the span is counterbalanced by weights, and mechanical energy has to be applied to begin raising or lowering it. In the past, there were employees who were permanently assigned to operating bridges. In recent years, staffing changes have taken place, and now the employees of the Beauharnois Locks are assigned in turn to operate the bridges. Thus, a person can work either at one of the locks or as a bridge operator. In recent years, changes also have been made in bridge maintenance. The established schedule calls for maintenance to be performed every second year on the Saint-Louis and Valleyfield bridges. During the winter of 1997-1998, however, planned major electrical maintenance work on the Saint-Louis Bridge could not be entirely completed because of the ice storm that struck this region in January 1998. The substation serving the bridge was destroyed during the storm, and power was only restored in the middle of March.Analysis The manoeuvres undertaken to take way off the vessel did not produce the expected results because the helm was turned hard-to-port while the vessel still had a fair amount of way on. As the propeller's pitch is to the right, it was normal to use the helm to counter the vessel's tendency to turn head to starboard when the engine was set to full astern. This tendency to turn to starboard is greatest when the vessel stops making headway through the water. When the helm was turned hard-to-port, the vessel began to turn immediately, and under the effect of the current, the turn was much sharper than expected. The shoal near the south shore downstream of the Saint-Louis Bridge is about 250 m from shore and 300 m upstream of the high-tension hydro towers, the approximate position of the GRANT CARRIER when she began manoeuvring to return to the channel. This shoal is covered with 4.26 m of water at chart datum, and the vessel's after draught was 7.98 m. At 0117, an electrician was dispatched to the Saint-Louis Bridge to determine the cause and attempt a repair of the malfunctioning green lights. The source of the malfunction was found to be switch No. 42D, as shown on one of the plans of the bridge. This switch performs two functions: it stops the bridge when the span has reached its raised position, and it activates the lights. There is a second switch (No. 42D1) that stops the bridge if switch No. 42D does not work properly. However, this second switch only stops the vertical motion of the bridge; the lights are not connected to it. Switch No. 42D was worn to the point where the light's electrical contact could not be made on the first and second tries. The contacts used to stop the span in the open position functioned properly, but the second function of simultaneously activating the lights with a different set of contacts did not work, and the bridge operator was unable to do this manually. Once the bridge operator activates the bridge opening/closing control, the bridge rises or descends to a predetermined point just before the operation is completed, whereupon it slows down to reach its final position, and stops automatically. The operation can also be performed manually. As the bridge's green lights did not come on when the span reached the open position, the bridge operator could not authorize the vessel to pass. The lights serve only to control traffic and/or give authorization to proceed. Even though the green lights did not come on, the vessel could have passed under the bridge safely. However, authority to allow vessels to proceed in such circumstances rests with the Saint-Lambert Traffic Control Centre (Seaway Beauharnois), which has jurisdiction in this area. The weight of the span is counterbalanced by weights, and mechanical energy has to be applied to begin raising or lowering it. In the past, there were employees who were permanently assigned to operating bridges. In recent years, staffing changes have taken place, and now the employees of the Beauharnois Locks are assigned in turn to operate the bridges. Thus, a person can work either at one of the locks or as a bridge operator. In recent years, changes also have been made in bridge maintenance. The established schedule calls for maintenance to be performed every second year on the Saint-Louis and Valleyfield bridges. During the winter of 1997-1998, however, planned major electrical maintenance work on the Saint-Louis Bridge could not be entirely completed because of the ice storm that struck this region in January 1998. The substation serving the bridge was destroyed during the storm, and power was only restored in the middle of March. When the span reached the open position, the green lights allowing passage under the bridge did not come on. When the green lights did not come on, the bridge operator immediately alerted the vessel. He did not, however, have the authority to let the vessel pass under the bridge. Manoeuvres to take way off the vessel and stabilize her in the current did not produce the expected results. During manoeuvres to bring the vessel back within the limits of the channel, the GRANT CARRIER struck a shoal. The bottom contact damaged the vessel and caused an ingress of water in the No. 4 port ballast tank. The switch that activates the green lights when the span has reached its maximum height (open position) was worn to the point where electrical contact could not be made at the first two tries. Even though the green lights did not come on, the vessel could have passed under the bridge safely. However, authorization to proceed had to come from the Saint-Lambert Traffic Control Centre (Seaway Beauharnois), which has jurisdiction in this area. Preventive maintenance on the Saint-Louis Bridge was not entirely completed during the winter preceding the 1998 shipping season. There was no defect in the vessel's equipment or engines that could have contributed to this occurrence.Findings When the span reached the open position, the green lights allowing passage under the bridge did not come on. When the green lights did not come on, the bridge operator immediately alerted the vessel. He did not, however, have the authority to let the vessel pass under the bridge. Manoeuvres to take way off the vessel and stabilize her in the current did not produce the expected results. During manoeuvres to bring the vessel back within the limits of the channel, the GRANT CARRIER struck a shoal. The bottom contact damaged the vessel and caused an ingress of water in the No. 4 port ballast tank. The switch that activates the green lights when the span has reached its maximum height (open position) was worn to the point where electrical contact could not be made at the first two tries. Even though the green lights did not come on, the vessel could have passed under the bridge safely. However, authorization to proceed had to come from the Saint-Lambert Traffic Control Centre (Seaway Beauharnois), which has jurisdiction in this area. Preventive maintenance on the Saint-Louis Bridge was not entirely completed during the winter preceding the 1998 shipping season. There was no defect in the vessel's equipment or engines that could have contributed to this occurrence. The GRANT CARRIER struck bottom downstream of the Saint-Louis Bridge because the vessel left the channel while trying to take off way and the manoeuvres to stabilize her in the current did not produce the expected results. The vessel was forced to reduce speed and finally stop because the green lights allowing passage under the Saint-Louis Bridge did not come on. The switch that activates the green lights when the bridge reaches the open position was worn. Preventive maintenance on the Saint-Louis Bridge was not entirely completed during the winter preceding the 1998 shipping season.Causes and Contributing Factors The GRANT CARRIER struck bottom downstream of the Saint-Louis Bridge because the vessel left the channel while trying to take off way and the manoeuvres to stabilize her in the current did not produce the expected results. The vessel was forced to reduce speed and finally stop because the green lights allowing passage under the Saint-Louis Bridge did not come on. The switch that activates the green lights when the bridge reaches the open position was worn. Preventive maintenance on the Saint-Louis Bridge was not entirely completed during the winter preceding the 1998 shipping season. During the winter of 1998-1999, modernization and automation work was performed on the Saint-Louis and Valleyfield bridges. According to those responsible, some employees prefer not to serve as bridge operators and, in the future, consideration will be given to this fact in giving out assignments.Safety Action During the winter of 1998-1999, modernization and automation work was performed on the Saint-Louis and Valleyfield bridges. According to those responsible, some employees prefer not to serve as bridge operators and, in the future, consideration will be given to this fact in giving out assignments.